Hydraulic hoist for dumping-vehicles



G. W. BERRY.

HYDRAULIC HOIST FOR DUMPING VEHICLES,

APPLICATION FILED JUNE 9,1919.

1 ,394,245. Patented Oct. 18, 1921.

2 SHEETSSHEET I.

G. W. BERRY.

HYDRAULIC HOIST FOR DUMPING VEHICLES.

APPLICATION FILED JUNE 9,19I9.

Patentecl Oct. 18, 1921.

2 SHEETS-SHEET 2.

G. W BQW" Svvocwboz anew mg UNITED STATES PATENT OFFICE.

U GEORGE w. BERRY,- or KANE, PENNSYLVANIA.

HYDRAULIC HOIST FOR DUMPIHG-VEHICLES.

Application filed. June a,

of Pennsylvania, have invented certain new and useful Improvements in a Hydraulic Hoist for Dumping-Vehicles, of which the following is a specification.

This invention has for its object to provide an improved hoist of the hydraulic type designed for application to dumping motor vehicles and which embodies an improved hoisting device consisting essentially of companion sets of hollow fluid operated and telescoping pistons specially constructed to withstand the strain imposed thereon incident to the elevation of the tiltable vehicle body upon an uneven roadway and the consequent tendency of the body to swing laterally.

Another object is the provision'of a hydraulic hoist for vehicle bodies in which the power of the propelling motor for the vehicle is utilized to pump liquid from a reservoir into the hoisting devices to effect rapid elevation of the body, a valved return pipe having a restricted passage being connected with the hoisting pistons whereby the fluid is returned to the reservoir to permit thebody to descend at a comparatively slow rate, according to the size of the restricted opening so as to prevent injury to the vehicle body chassis incident to the rapid fall of the body.

Another object is the provision of an automatic pressure controlled release valve in the piping system of the hydraulic hoist by which the liquid passing through the liquid feed pipe is returned to the reservoir when the fluid pressure exceeds a predetermined value.

With these and other objects in view as will appear as the description proceeds, the invention comprises the novel features of construction combination of elements and arrangement of parts which will be more fully described in the following specification and set forth with particularity in the claims appended hereto.

Figure 1 represents a fragmentary side elevation. of a vehicle illustrating the improved hydraulic hoist applied thereto.

Fig. 2 represents a fragmentary plan view I of the vehicle, the tiltable body being removed. v Fig. 3 represents a vertlcal sectional view Specification of Letters Patent.

Patented Oct. 18, 1921.

1919. Serial No. 302,880.

taken transversely of the vehicle chassis through one of, the hoisting devices illustratmg the telescoping piston structure in detai Fig. 4 represents an enlarged sectional view through the manually operable valve controlling the admission of liquid'to the hoisting devices and reservoir.

Fig. 5 is a detailed sectional elevation of the safety or relief valve.

Referring to the drawing, wherein similar reference numerals designate corresponding parts throughout the several views, the numeral 5 indicates the chassis of a conventional typeof motor vehicle provided with the usual rear drive wheels 6 having connection with the propelling engine of the vehicle (not shown) by a main drive shaft 7 and variable speed transmission 8. A tiltable body 9 is pivotally supported in brackets 10 located adjacent the rear terminal of the chassis 5 whereby the forward portion of the body may be elevated, as suggested in dotted lines in Fig. 1 to dump the contents thereof.

In applying the improved hydraulic hoist to the vehicle a tank or reservoir 11 is adequately supported in the chassis 5 and is connected by a pipe 12 with a pump cylinder 13 provided with a drive gear wheel 14: engageable with a sliding gear 15 keyed for rotary movement with the drive shaft 7 but movable longitudinally thereof whereby the gear 15 may be moved into and out of mesh with the wheel 14 to establish a driving congear 15 in such manner that oscillatory movement of the lever 16 effects adjustment of the gear Wheel 15 longitudinally of the shaft 5. I

The pipe 12, as will be understood, is connected with the inlet port of the pump cylinder 13 while the outlet port is connected by a fluid supply pipe 17 with a pair of companion hoisting devices designated generally by the numerals 18. A return pipe 19 connects the supply pipe 17 with the reservoir 11 whereby the liquid from the hoisting devices 18 is returned to the reservoir. A valve casing 20 is connected at the point of intersection of the pipes 17 and 19 and is provided with a manually operable rotary till valve :23. having a substantially T-shaped passage therein whereby liquid may he conducted from one portion of the pipe 17 to the other portion thereof without having access to return pipe 19 or, if desired, by proper adjustment of the valve commun cation between the pump 13 and the hoisting devices 13 is shut oil and the fluid remaining in the hoisting devices is admitted to return to the reservoir through the relatively short radially disposed port and a portion of the diametrical port in the valve 21.

In order to prevent the pressure in the pipe 1? from becoming dangerously high, as when the tiltable body 9 is elevated to the limit of its upward movement and the operator fails to disconnect the gear wheel 15 from the gear Li, a relief pipe 23 having an automatic fluid pressure relief valve 24 of any conventional t'orm as shown in Fig. 5 ot' the drawing therein is provided. The valve 2% is preferably set so as to withstand pressure up to 550 pounds and when the pressure in the pipe 17 exceeds this amount the valve 2a is automatically opened permitting the liquid to return to the reservoir 11 and thus circulate through the pipe 12,

7 pump 13, portion of the pipe 17, valve 24 and relief pipe 23.

Supplementary transverse supporting beams 25 are secured in the vehicle chassis 5 and have attached thereto depending brackets 26 having apertured lower terminals receiving the diametrically opposed trunnions 27 carried by the cylinders 28 of the hoisting devices 18, whereby the latter are pivotally mounted in the vehicle chassis 5 so as to permit them to swing to accommodate the tilting movement of the body 9 when the latter is elevated upon the tulcrum 10. The adjacent trunnions 27 of the companion cylinders 28 are connected with lateral branches 27 of the rear terminal of the supply pipe 17 and angular fluid pipes 28 connect the passages 29 in the hollow trunnions 27 with the lower ported heads 30 oi. the cylinders whereby fluid from the supply pipe 17 is admitted to the cylinders to effect maximum elevation of the telescoping pistons which are reciprocably mounted therein.

An outer hollow piston 31 is reciprocably mounted in each cylinder 28 and a capshaped head 32 is fitted upon the lower terminal thereof and provided with axial recess receiving a threaded sleeve 33 having communication with the lower portion of the cylinder 28 and the interior of the hollow piston 31. The lower terminal of the sleeve is flanged :tor the retention of a flanged packing ring 34 the flange of which is so arranged as to be automatically expanded against the internal wall of the cylinder Q8 by the liquid pressure in the cylinder thereby establish fluid tight joint preventing the admission of the liquid into the chamber above the cap-shaped head 32. The movement of the upper portion of the outer piston 31 is guided by the upper terminal of the cylinder 28'' and an inner piston 35 carrying a head 36 at its lower terminal 13 reeiprocabl y mounted in the outer piston 31 and is provided with a flanged packing ring 37 similar in construction'to the ring 34 adapted to be actuated by the fluid pressure in the cylinder to maintain the fluid tight joint during elevation of the vehicle body 9. The upper portion of the inner piston 35 is received within a guide collar 38 removably fitted in the upper terminal of the outer hollow piston 31 and a spherical head 39 is formed at the extreme upper terminal of the piston 35 and is movably received within a two-part socket 40 secured to each side or the under portion of the tiltable body 9 wfiereby the pistons 35 are connected therewit In its normal position, the body 9 is supported upon the truck chassis 5 and the oil or other liquid is contained in the reservoir 11. When it is desired to elevate the forward portion of the truck body to unload the contents thereof, the lever 16 is shifted so as to move the gear wheel 15 into mesh with the gear 14 thus establishing a driving connection between the drive shaft 7 and the pump 13 which, when the drive shaft is operated causes the liquid to be drawn from the reservoir 11 through the pipe 12 and, when the valve 21 is adjusted so as to register the diametrical port thereof with the sections of the supply pipe 17 the latter conducts the oil into the pipes 28 and lower portions of the cylinders 28". Owing to the relative size of the pistons 31 and 35, the piston 31 is elevated in advance of the piston 35 and as the piston 31 is moved to the limit of its upwardmove'ment the inner pistons 35 are acted upon and elevated to the extent of their movement thus carrying the forward portion of the body 9 upwardly into such position as to "facilitate unloading of the contents thereof. As will be understood, the liquid finds its way into the interior of the hollow piston 31 through the bore of the sleeve 33. in order to maintain the vehicle body in ele vated position for an extended period, the valve 21 is adjusted so as to close communication with the rear portion of the supply pipe 17, as shown in Fig. at of the drawing and thus the liquid is maintained in the rear portion of said pipe and in the cylinders 28 and the several hollow pistons 31 and 35. Should the operator neglect to disengage the gear wheel 15 from the wheel 1% subsequent to closing the valve 21 the pressure produced in the forward portion of the supply pipe 1'? incident to the continued operation of the pump 13 is relieved by the automatic relief valve 24 which is constructed and arranged to permit the liquid to return to the reservoir 23. When it is desired to lower the vehicle body to its initial position, the valve 21 is adjusted, so as to establish communication between the rear portion of the supply pipe 17, and the return pipe 19 and thus the liquid standing in the hollow pistons, cylinders and pipes 17 is permitted to return to the reservoir 23. In order to retard the downward movement of the vehicle body and prevent rapid descent thereof, the pipe 19 is preferably formed with an internally restricted portion 41 which controls the admission of liquid to the reservoir and correspondingly controls the rate of descent of the wagon body.

What I claim is:

1. In a hydraulic hoist for dumping vehicles, a reservoir, hydraulic hoist means, a lead between the reservoir and hoisting means, a pump interposed in said lead for feeding liquid to the hoisting means under pressure from the reservoir, a pipe connecting the portion of the lead between the pump and hoisting means with the reservoir, an automatic relief valve within the pipe and adapted to be automatically actuated when the pressure between the pump and hoisting means exceeds a predetermined value to permit the liquid to return to the reservoir and a return pipe connecting the reservoir with the lead between said pump and hoisting means and having a restricted passage.

2. In a hydraulic hoist for dumping vehicles, a liquid reservoir, hydraulic hoisting a pressure relief pipe connecting the reservoir with the lead at a point intermediate the pump and the first-named pipe and provided with a pressure relief valve adapted to automatically open when the pressure of the lead exceeds a predetermined value to permit the liquid to return to the reservoir.

In testimony whereof, I affix my signature hereto.

- GEORGE W. BERRY. 

